Supplementary tests

Cytomegalovirus (CMV)

This is a very common virus, which causes a mild ‘flu-like’ illness. People in good health make a full recovery and are only aware of having had “a virus”.

We test for antibodies and a positive result indicates that the person has had CMV infection and may still be carrying the virus. 50% of the population have had CMV by the age of 50 and we do not tell you about this test result as it is of no significance to your health. In patients with a poor immune system, however, (bone marrow recipients or small babies) CMV can be a dangerous illness which is why we have to ensure that they receive blood which does not have the virus.


This is a parasite called Trypanosoma cruzi. It is found in certain parts of Central and South America and is transmitted by biting insects or from mother to baby at the time of birth or through blood transfusion received in this part of the world. Carriers of the parasite are at risk of developing Chagas’ Disease, which can cause destruction of the muscles of the heart and intestines. Not all carriers become ill.

Our test looks for antibodies to the infection. A donor’s place of birth, their mother’s place of birth, the donor’s travel history or history of transfusion in certain parts of Central and South America determines whether the test is required.


People who have lived in or visited a tropical area may be at risk of being infected with malaria, which is transmitted by mosquitoes. People who have had malaria produce antibodies to the parasite. These antibodies usually disappear on recovery from the disease. However, some people who appear to have recovered, are still able to carry the parasite and therefore continue to produce antibodies. We have introduced a test that looks for malaria antibodies.  A positive result means that at some time in the past that person has been infected with malaria and may still be carrying the parasite.